Ingeniously incorporating hollow mesoporous silica into waterborne polyurethane film to improve water vapor permeability

摘要

? 2022 Elsevier B.V.Incorporating hollow mesoporous silica (HMS) into waterborne polyurethane (WPU) to improve water vapor permeability (WVP) remains a major challenge. Herein, HMS-I and HMS-II with large hollow size and mesoporous structure were prepared with n-hexane as pore-expanding agent, and template was removed by calcination and extraction, respectively. Then, HMS/WPU composite emulsion was prepared by dispersing the pre-prepared polyurethane prepolymer terminated by 3-(aminopropyl)triethoxysilane (APTES) into aqueous medium containing HMS particles, with the help of co-condensation between silanol on HMS surface and silanol produced by Si-OEt hydrolysis of APTES. The results showed that the WVP of the composite film was greatly improved, especially HMS-II/WPU was better than HMS-I/WPU. This design strategy provides a prospect for the preparation and extensive application of HMS/WPU functional composites.